Article made of chromium



Jan. 19, 1932. s R, MASON 1,842,037 T ADE 0F crmomum Filed March 6, 1929 F497 529.3. I V

@0672 if 5117777767R Masm .vision of articles, such as tubes and dies,

Patented Jan. 19, 1932 UNITED STATES PATENT OFFICE SUMNER REDWAY MASON, OF WILMETTE, ILLINOIS, .ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK ARTICLE MADE OF CBIROMIUM Original application filed April 12, 1928, Serial No. 269,441. Divided and this application filed March 6,

1929. Serial No. 344,844.

This invention 'relates to articles made of chromium and has for its. object the promade of chromium.

This application is a division of my copending application Serial No. 269,441, filed April 12, 1928.

In accordance with the general features of the invention, a tubular article embodying the invention may be made by depositing a coating of chromium of the thickness desired in the finished tube upon a core made of a metal or alloy 'other than chromium. The core is then removed from the chromium deposit by means of a reagent which dissolves the core and leaves the chromium unaffected,

or if the melting'point of the material of which the core is made is 'sufiiciently low, the core may be melted away from the chromium coating. The resulting tube may then be used for any suitable purpose without further change, or it may be surroundedby reinforcing metal and serve as the drawing surface of a drawing die or similar devlce.

A clear understanding of the invention may be had from the following detailed description thereof and the accompanying drawings, in which Fig. 1 is a perspective VlBFV Of a core which may be employed in practicing the method embodying the invention; Fig. 2 is a perspective view of the core shown in Fig. 1 coated with a deposit of chromium;

Fig. 3 is a chromium article embodying the invention, which may be produced by the method of this invention; K

Fig. 4 is an elevational view of another type of core which may be used in practicing the invention; i I

Fig. 5 is a longitudinal, sectional view of the core shown in Fig. 4 with a deposit of chromium thereon;

Fig. 6 is a sectional View of a tubular shell of chromium which may be made by prac ticing the invention;

Fig. 7 illustrates the shell shown in Fig. 6 with a coating of copper thereon;

Fig. 8 is a perspective view, partially broken away, of a wire drawing die embodying the nvention, and

Fig. 9 1s a perspective view of another form of. wire drawing die embodying the invention.

In practicing the method embodying the invention for the purpose of manufacturing tubular articles made of chromium, a rod shaped core 10 made of a metal other than chromium, such as a fusible alloy, is coated with a layer of chromium 11 of the thickness desired in the finished tubular article, and the core 10 is then removed from beneath the layer of chromium 11. The layer of chromium 11 may be placed upon the core 10 in any manner well known to the art, such as by electrolysis from an electroplating bath having chromic acid as its principal constituent. The core 10 may be removed from beneath the layer of chromium 11 by means of a reagent, such as nitric acid, which dissolves the material of which the core is made and leaves the chromium unattacked; or else if the core is made of the material having a low melting point, the core may be melted away from the coating of chromium. The resulting tubular article consisting entirely of chromium may be used for any suit able purpose wherein the desired properties of chromium, such as its hardness, wear resistance, and resistance to corrosion, make it advantageous to use such articles.

The method embodying the invention may also be used with very satisfactory results in the manufacture of dies, such as wire drawing dies, having a wearing surface of chromium. In the manufacture of dies of this type, a core 20 having a circular cross section is made of a material other than chromium with a highly polished surface 21 having the contour desired in, the wearing surface of the finished die formed thereon. A layer of chromium 22 is deposited upon the core 20 to a depth sufiicient to form a rigid tubular shell of chromium, and the core 20 is removed from the layer of chromium 22 in any suitable manner, such as by dissolving or melting the core. The resulting tubular shell of chromium 22 is then coated with a thin coating 23 of another metal, such as copper, to which soldering material will adhere readily, and the coated tubular shell of chromium is then secured within a central aperture 24 formed within a body of reinforcing metal 27 by means of any suitable material, such as solder 25. If necessary, the block of metal 27 may be trued after the tubular shell of chromium 22 has been secured therein in order to align the edges thereof with the axis of the tubular shell, and the resulting die may then be employed in wire drawing or'other similar operations.

Another method of making wire drawing dies in accordance with the invention is to prepare a chromium shell 122 similar in form to the shell 22, described hereinbefore, and

then cast a block of reinforcing metal 127 directly around the chromium shell 122. In this case, the necessity of plating the chromium shell with another metal. such as copper, is avoided, since the metal 127 will conform to the shape of the outer surface of the chromium shell 122 and will retain the shell securely therein.

By making, either the core member 10 or the core member 20 of a material other than chromium, the core may be readily removed from a layer of chromium deposited thereon, and by making the surface of the core upon which the chromium is deposited of the shape desired in the wearing surface of the finished "article, the chromium may be easily formed into the desired shape by a deposition of the chromium thereon. By providing a highly polished surface upon the core, the surface of the layer of chromium adjacent the polished surface of the core will also be extremely smooth and mirror-like in character so that when the core is removed from the layer of chromium. the above mentioned surface of the rcsultin shell of chromium is of such character that no further polishing or forming operations are necessary in order to prepare this surface for use as the drawing surface of a die. etc.

From the foregoing description, it will be readily seen that this invention provides useful articles made of chromium and a simple and practical method by means of which such articles may be produced. It is to be understood. howcver, that the embodiments of the invention illustrated herein are merely useful examples illustrating the invention and that the invention is limited only by the spirit and scope of the annexed claims.

lVhat is claimed is:

1. As a new article of manufacture, a die composed of a body of metal having a central aperture therethrough and a shell of chromium coated with copper soldered within the aperture in the body of metal.

2. A wire drawing die comprising a body of metal provided with an a erture, and a chromium shell soldered within the aperture to secure it therein and to provide a yieldable backing for the shell.

3. A wire drawing die comprising a body of metal provided with an aperture tapered from one end thereof to the other, and a cop- SUMNER REDWAY MASON. 

